Method and apparatus for forming plaster board



April 20; 1926. 1,581,328

' J. SCHUMACH ER 'METHOD AND APPARATUS FOR FORMING PLASTER BOARD Filed Feb. 24, 1925 5 Sheets-Sheet 1 gwumfloz April 20 1926. 1,581,328

J. SCHUMACHER METHOD AND APPARATUS FOR FORMING PLASTER BOARD Filed Feb. 2 1925 3 Sheets-Sheet 2 A ril 20,1926. 1,581,328

' J. SCHUMACHER METHOD AND APPARATUS FOR FORMING PLASTER BOARD Filed Feb. 24, 1925 s Sheets-Sheet 5 iii? Patented Apr. 20, 1926.

UNITED STATES PATENT OFFICE.

METHOD AND APPARATUS FOR FOB HING-PLASTEB BOARD.

Application filed February 24, 1925. Serial No. 11,189.

To all whom it may concern:

Be it known that I, JOHN SCHUMACHER, a citizen of the United States. residing at Los Angeles, in the county of Los Angeles and State of California, have invented a new and useful Method and Apparatus for Forming Plaster Board. 1

This invention relates to a method and apparatus for forming plaster board.

With the method and apparatus for forming plaster board heretofore employed the edges of the plaster board as formed are rough and uneven and hence it is necessary to cut away a portion of the board and trim the same to form a finished product. This involves considerable expense and waste of materials.

It is an object of the present invention to provide a method and apparatus for forming plaster board, which is adapted to form a finished edge upon the plaster board as the board is formed to the end that the ordinary expense of cutting away and trimming the edges of the plaster board as formed may be eliminated and that a decreased waste be obtained in the formation of the plaster board.

Various other objects and advantages of the present invention will be apparent from a. description of a preferred form of the method and apparatus for forming plaster board embodying the invention. purpose reference is made to the accompanying drawings illustrating a preferred form, or example, of an apparatus for forming plaster board embodying the invention and by the use of which a preferred method of forming plaster board may be practiced.

In the drawings:

Fig. 1 is a side elevation partially in vertical section of the apparatus.

Fig. 2 is a plan view, part of the feeding and trimming apparatus being removed.

Fig. 3 is'an enlarged front elevation of the spreading and forming means.

Fig. 4' is a section on the line 4-4 of Fig. 3. 1

Fig. 5 is a fragmentary elevation, partially in vertical section of certain parts of the forming and spreading means, and.

Fig. 6 is a section on the line 66 of Fig. 5.

Referring to the drawings, the apparatus there illustrated comprises ahopper 2 for holding and supplying plastic or cementiti- For this ous material which is to be incorporated in the plaster board. 3 indicates a mixer for mixing the plastic or cementitious material with water supplied from a pipe 4, the mixer 3 preferably consisting of a trough in which are mounted rotatable mixing blades 5, the blades being mounted upon a a sheet or strip'supplied from the roll 9 as the upper sheet of the plaster board forms.

The sheets 10 and 11 are indicated as passing to the plaster board forming a spreading means generally indicated at 12. Suitable advancing means 13 are provided for continually conveying the plaster board being formed to the discharge end of the apparatus, such advancing means being indicated as comprising a conveyor 16. The advancing means 13 is adapted to discharge successively separate portions of the formed plaster board upon a receptacle such as a truck (not shown).

The spreading and forming means 12 of the apparatus include an upper roller 20 and a lower roller 21, spaced apart to determine the thickness of the finished board. As the sheets 10 and 11 are fed between the rollers 20 and 21, plastic or cementitious material is fed from the hopper 2 onto a box 17 likewise positioned on the advancing means 13 from which the plastic or cementitious material is spread by the rollers 20 and 21 and with the sheets 10 and 11 formed to a proper thickness of plastic board. In so far as the apparatus and method of forming plaster board has been particularly described, it is similar to the present generally accepted apparatus and method particularly described and claimed in Patent No. 1,176,322,

granted to John Schumacher and Joseph E.

Schumacher, March 21, 1916.

With the ordinary type'of such plaster board method and apparatus the edges of the board as they leave the forming and spreading means 12-are irregular and the unequal edges must be cut off and the board trimmed with a corresponding waste of material and increased production cost. By

lbs.

themethod and apparatus of this invention, these disadvantages are overcome.

In accordance with the principles of this invention, the sheets of fibrous covering material 10 and 11 fed to the spreading and forming means are made substantially equal length to the rolls 20 and 21 of the spreading and forming means. This, of course, may be accomplished by the use of rolls 8 or 9 of the fibrous covered material substantially corresponding in width with that of the rolls 20 and 21. In order to insure the sheets supplied to the spreading and forming means 12 being of the roper thickness to correspond with such rol s, however, is generally preferable to provide a trimming means for the sheets positioned in advance of the rolls 20 and 21. 22 and 23, respectively, generally indicate suitable trimming means for-therespective sheets 10 and 11. These trimming means may be of any desired or preferred form such as disc knives 24 and 25, respectively, and may be driven in any desired manner. v

Where mention is made of the provision of the feeding or trimming of sheets 10 and 1.1 to correspond with the width of rolls 20 and 21 of the spreading and forming means, it is understood that the sheets 10 and 11 are made to be of equal length with the rolls 20 and 21, as they pass therebetw'een. Inasmuch as the contact with the moist plastic or cementitious material supplied from box 17 causes in operation a slight swelling of the sheets 10 and 11 amounting to a fraction of an inch the trimming of the sheets by the devices 22 and 23 are governed accordingly. This makes the sheets 10 and 11 as cut by the trimming means slightly narrower than the width of the rolls 20 and 21.

In carrying out the objects of the invention a method and apparatus is providedfor con tinually smoothing the edges of the plaster board as formed in order that a smooth clean edge will be obtained. Hence trowels 26 are provided at each end of the rolls 20 and 21. The trowels 26 may be of various constructions'and operated at different manners, the essential feature of the invention being the provision of a driven or moving trowel 26 for continually trowelling or smoothing the edges of the plaster board as it is formed. The term trowelling is employed herein to indicate the operation of smoothing and forming the edge of the plasterboard by a motion of a forming tool, such as'the trowels 26,-relatively transverse to the plasterboard as formed, so that the board, while being formed, is not only provided with a wall to limit the outward motion of the plaster, but such wall is given a smoothing and edgeformin motion relative to the plasterboard to proc uce the desired finished edge. The

members 26 are trowels, since during each rotation such members pass once downwardly transverse to the formed board and then upwardly transverse to the formed board, thus rounding the corners of the board and forming a smooth edge. In the specific form of the invention the trowels 26 are illustrated as discs mounted flush against the ends of the upper roller 20 and extending as a flan e therefrom down against the edges of tie lower roll 21 where the plaster board is formed. Such trowels, of course, could be attached to the roll 20 in variouslnanners. However, for reasons hereafter apparent they are preferably allixed thereto in the following manner.

An annular trowel supporting body 27 is mountd on the end of the shaft or axle 28 of the roll 20. This body is then bolted or otherwise secured to the rolls 20 as indicated at 29. The body 27 is provided with an annular recess 30 for the reception of the inner end of the disc trowel 26 and the trowel is then held thereto by bolts or pins 31. The trowel supporting body 27 is cylindrical in form and serves to mount a trowel cleanser 32, which is preferably fixed against rotary motion and held on the body 27 by a plate 33 secured by means 34 to the body 27. The cleaning member 32 is recessed as indicated at 35 to fit the disc trowel 26 and thus is adapted to clean or remove the rear face and edge of such member from any plastic or cementitious ma terial or other matter tending to accumulate thereon. The contact surfaces between the cleanser 32, disc trowel 26, trowel support.- ing body 27 and plate 33 are lubricated and kept clean by lubricant supplying means 36 and 37. Such means include suitable lubricant containers 38 and 39, respectively, for

holding lubricant under pressure of feeders 40 and 41 actuated by springs 42 and 43, respectively. From the container 38 the lubricant flows through line 44 in the cleanser 32 through lateral Ways 45 to oil grooves 46 and 47 on the confronting surfaces of the trowel 26 and the cleanser Lubricant also passes from line 44 to an oil groove or grooves 48 on the confronting surfaces between the trowel supporting member 27 and the cleanser 32. Lubricant from the chamber 39 passes through the line 50 to an oil groove or grooves 51 on the con fronting surfaces between the body 27 and cleanser 32 and thence through way- 52 to oil groove 53 on the confronting surfaces between the plate 33 and cleanser 32.

Preferably in order to facilitate the dissembling of the apparatus or to permit rollers of different sizes to be used as the forming and spreading means, the roller 20 is made in three sections, of which 5-1 is a central or main section of the roller 20 and 55 indicates one of the two end sections provided. This permits the length of the roller to be readily varied. The end section til) is indicated as split and held together and to the shaft 28 by a bolt 55.

As an additional method and means of insuring a finished edge being formed on the plaster board, it is desirable to provide means for continually maintaining the rollare 20 and :21 clean. For this urpose a wiper 57 is provisioned to continua 1y bear against the rear side of the roll -20. This wiper may be of any desired 'form, preferably maintained slightly moist.

As the plaster board is formed by rolls 20 and 21, there is a slight tendency of the roller 20 to pick up the formed board to carry the same therewith. This action operates to prevent the desired even edge being formed. In order to overcome this tendency; a bar 58 is provided contacting slightly with the roller 20, inthe position indicated in Fig. 4, where it' will arrest and prevent the plaster board from being carried or picked up by the roll 20. a

It will be apparent that by theuse of the herein described apparatus the fibrous sheets '11 and 12 are fed to the rollers20 and 21 of equal length therewith. The trowel 26 is continually driven as the plaster board is formed smoothing ofi the edges of the board and forming thereby a. finished appearing board. The trimmer 26' and rolls 20 are continually cleaned to prevent accumulation of hard material thereon, which hinders 'forn'iation of the finished edge. The formed plaster board is caused to pass directly away from the forming and spreading means and thus leaves the trowel and. finished edges unafiected until the plaster board is dried and used.

lVhile the method and apparatus for forming plaster board herein described is well suited for accomplishing the purposes of this invention, it is to be understood that various modifications in the details of the method and apparatus may be made without departing frontthe spirit of the invention, and the invention is not therefore limited to the specific form described, but is'of the scope set forth in the appended claims.

I claim: I

1. A method of forming plaster board which comprises continually trowelling the edges of the plaster board as the same is formed by incorporation of mentitious material between ing sheets.

2. The method of forming plaster board which includes continually trimming fibrous covering sheets to the size of the desired brous coverfinished plaster board, continually su ply .ing plastic or cementitious material t ere-j between, and continually trowellin'g the edges of the formed board at the point of incorporation of the plastic-or cementitious material.

3. The method of forming plaster board,

' for supplying plastic or ce-' which includes continually passing fibrous covering sheets to forming and spreading rollers, continually supplying plastic or ce mentitious material between the sheets at the rollers, the sheets being so supplied that as the boards are formed they are of equal length with the rollers, and continually trowelling the edges of the board as formed.

ling the edges of the board as formed to form a plaster board with a'finished edge, and restraining the plasterboard as formed from being picked up by the forming or spreading ro lers.

5. The method offorming plaster board comprising continually advancing fibrous covering sheets to spaced rollers, continually feeding cementitious or plastic material between the sheets as passed between such rollers, the sheets advanced to the rollers being of equal length therewith as "they pass therebetween, and-continually trowelling the edges of the plaster board as formed.

6. An apparatus for forming plaster board comprising-fibrous covering material supply means, forming and 3 reading means, means for advancing the brous covering material to the forming and spreading means and conveying the same therefrom, means lastic or cementitious material between t e fibrous coverin'g materials at the forming and spreading means, and trowels positioned to engage the edgesof the plaster board as formed, and means for continually actuating said trowels.

7. An apparatus for forming board com rising means for continually advancing brous material, means for supplying plastic material between said brous material as the ,sameis advanced, means for trimming the fibrous material to predetermined size prior to tion of plastic material, trowels disposed in engagement with the edges of the p aster board as formed, and means for moving the trowels to form finished edges on the board.

8. An apparatusfor forming plasterboard comprising fibrous material su ply means,

plastic material sup ly means, orming andplaster addioperative to produce finished edges on m i board, andfmeans engageable with the boardas formed operative to restrain said rollers picking up the board.

9, An apparatus for board, comprising fibrous material supply forming plastermeans, means for supplying plastic material between supplied fibrous material, forming and spreading rollers, and trowels mounted on the rollers for finishing the edges as formed. v

10. An apparatus for forming plaster board comprising means for continually advancing fibrous material, means for interposing plastic material between spaced sheets of the fibrous material, rollers operative to spread said plastic material, trowels at the ends of the rollers, means for moving the trowels to finish the edges of the produced board, and means for continually cleansing the trowels.

11. An apparatus for forming plaster boa-rd comprising forming and spreading rollers, means for advancing fibrous material to said forming and spreading rollers, means for supplying plastic material at the rollers, means carried by the rollers for producing finished edges, trowels at the ends of the rollers, and means for cleaning the trowels.

Signed at Los Angeles, California this 19 day of February, 1925.

JOHN SCHUMACHER. 

